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Re: Home VSH Testing

liquid nitrogen is nice because it freezes quickly, then boils off quickly. If you're wanting to test for brood removal, perhaps dry ice would be an acceptable substitute. It can be pulverized into a granular powder easily by placing into a sturdy container, and whacking it with the top of a claw hammer or piece of wood. Shaking the container the way one would flip an egg in a skillet without a spatula will raise any un-pulverized chunks to the surface for another round of pulverization. Or, you could sift through 1/4" hardware cloth.

If you do use the dry ice, know that because it takes longer to sublime than liquid nitrogen does to boil, the area that will be frozen will be a bit larger than the area of application.

Pete. New 2013, 7 hives, zone 6a
To study and not think is a waste. To think and not study is dangerous.

Re: Home VSH Testing

> perhaps dry ice would be an acceptable substitute.

When discussing this with Marla Spivak she said dry ice did not work well. It often did not kill the brood. If you really don't want to buy the dewar and the liquid nitrogen, I'd either do the pin prick method (which Marla says isn't as good because there are two behaviors involved and one is uncapping which you skip with this method) or cut the section out and freeze it in your freezer overnight, thaw it, and then put it back in the hole you made and see how fast they uncap it.

Re: Home VSH Testing

Marla Spivak recommended against using dry ice at last year's EAS in Vermont. Instead, she suggested using a round cookie cutter to punch out a section of capped brood from a frame (of wax foundation without wires), put it in a freezer overnight, then put it back in place the next day (after thawing).

She actually recomended using the cookie cutter over liquid nitrogen for people that weren't doing dozens of tests a day. She said that she had to use the nitrogen because she couldn't wait 24 hours and then revisit the same site.